A plasma display panel (hereinafter, referred to as the PDP) has a front plate and a rear plate. The front plate has a glass substrate, a display electrode formed on one main surface of the glass substrate, a dielectric layer to cover the display electrode and serve as a capacitor, and a protective layer formed of a magnesium oxide (MgO) on the dielectric layer. Meanwhile, the rear plate has a glass substrate, a data electrode formed one main surface of the glass substrate, an insulating layer to cover the data electrode, a barrier rib formed on the insulating layer, and phosphor layers formed between the barrier ribs and emitting red, green, blue light, respectively.
The protective layer has two main functions. One is to protect the dielectric layer against ion bombardment at the time of discharging. The other is to emit an initial electron to generate an address discharge. When the dielectric layer is protected against the ion bombardment, a discharge voltage is prevented from rising. When the number of initial electron emissions is increased, an address discharge error causing a flicker of an image can be prevented. In order to increase the number of initial electron emissions, there is known a technique to add an impurity in the MgO, or a technique to form MgO particles on a MgO film (e.g., refer to Patent Documents 1, 2, 3, 4, and 5).